It is well known that a convalescing patient will spend a great majority of time in bed. Many different types of hospital beds have been developed to enhance the care and comfort of the patient during convalescent activities. For example, the bed structures disclosed in U.S. Pat. Nos. 3,822,425, 3,909,858, 4,488,322 and 4,638,159 are specifically designed to protect patients from the development of pressure induced lesions or bed sores during protracted patient convalesce. At times however, it is quite beneficial for patients to assume a comfortable sitting position and to move about. For this reason, many hospitals, nursing homes and other convalescent centers are provided with chairs for use by patients. In most cases, the chairs are simply large, stuffed chairs which provide for patient comfort. In many cases these chairs are covered with a water resistant material such as any one of a number of commercially available polymer materials which will not remove moisture from the patient and which will not provide for cooling of the patient. In fact, a great majority of the materials utilized for chair covers will retain heat and moisture rather than permit removal or dissipation of heat and moisture from the skin tissue of the patient. In virtually all cases hospital chairs are provided with seats which only provide for patient support and comfort and do not protect the patient against the development of pressure induced lesions.
Convalescing patients must frequently sit in chairs for extremely long periods of time without changing positions. Since in the sitting position majority of the patient's weight is applied to the seat portion of the chair the mechanical pressure between the patient's skin and the seat portion of the chair is frequently great enough for the development of pressure lesions. The skin and sub skin tissues of the patient contain a multitude of capillaries for circulating blood to the skin. If the mechanical pressure of the skin against the surface of a bed, chair is sufficiently great that the capillaries are collapsed or restricted, there is insufficient blood supply to portions of the skin tissue. This condition of poor blood supply causes the skin and sub skin tissue to deteriorate, thus developing pressure induced lesion or bed sores. The blood supply at the skin of the patient also provides for effective transmission of moisture from the patient in the form of perspiration. It is desirable therefore that the chair system provide effectively for removal of moisture from the patient and to also provide for cooling of the patient. Obviously under circumstances where ineffective cooling takes place certain areas of the patient's skin tissue is subjected to excessive heat which is a contributing factor to the development of pressure induced lesions. Further, moisture continuously present at the skin of the patient also enhances the development of pressure induced lesions and prevents efficient healing of the skin tissue after pressure lesions have developed. In the case of patients sitting in chairs, the skin tissue about the buttocks and thighs of the patient is frequently subjected to excessive mechanical pressure conditions which enhance the development of pressure lesions. It is desirable therefore to provide for efficient, even distribution of the weight of a patient over a substantial area of the seat portion of the chair to thus minimize the mechanical pressure induced to any portion of the patient's skin surface. It is also desirable to provide for efficient moisture removal and cooling from the bottom or seat portion of the chair to thus provide efficiently for patient comfort and to enhance therapeutic activity when the patient is in a seated position.
In many cases hospital chairs are merely plain stuffed, comfortable chairs. When elderly or physically unsound patients are sitting in these chairs the patient can slump to one side and become uncomfortable without possibility of being shifted to a comfortable position unless nursing personnel provides such assistance. It is desirable therefore to provide a chair system incorporating means for efficient support of the patient to prevent undesirable slumping. In many cases patients are connected to other therapeutic apparatus during the times they are seated in hospital chairs. For example intervenous fluid equipment may be utilized or the patient my be intubated such as with a trachea tube, food supply tubes, etc. It is desirable therefore to provide a chair system which will effectively prevent the patient from inadvertently dislodging other hospital apparatus while seated in a convalescent chair.